[Wolves] IP Aliasing

[Simon C. Burke]

----- "Simon C. Burke" <SimonB at geek-web.co.uk> wrote:

> On Thu, 2008-10-16 at 22:05 +0000, Andy Smith wrote:
> > Hi Simon,
> > 
> > On Thu, Oct 16, 2008 at 10:47:31AM +0000, Simon C. Burke wrote:
> > > Hi all.
> > > 
> > > I recently moved my mail server to a different box. However whilst
> changing IP I wanted to add the old one as an IP Alias.
> > > 
> > > I went through the usual rigmarole of running:
> > > 
> > > /sbin/ifconfig eth0:0 78.105.102.xx netmask 255.255.248.0
> > 
> > These days you should be using the "ip" utility..
> > 
> > Also the netmask for an alias on the same network as another
> > interface should be 255.255.255.255.  So:
> > 
> > # ip addr add 78.105.102.xx/32 dev eth0
> > 
> Bingo, there lay the problem. I removed the alias as I had previously
> done it and re added it as per above and it all works...
> 
> Though I'm now curious as to why it didnt work in the first place? As
> it
> was how my previous server was setup (Ubuntu also).
> 
> Thanks muchly for the assistance.
> 
I'll ammend my results now. It works fine internally on the LAN (my LAN is IP'ed with a external subnet) but it does not work externally.

Im guessing this is due to the default route of the box being via its other interface? hence the return traffic if coming from a different ip?

I'll have a play...

Regards,
Simon.